The Warriors have surrendered a 22 point halftime lead to slump to a 36-28 loss in their national rugby league match against the Panthers in Penrith.
The Warriors led 28-6 at halftime but crumbled as Penrith kept the Warriors scoreless in the second half and ran in five unanswered tries.
It's the biggest points lead the Warriors have surrendered to lose an NRL game, in their 22 year history.
It's only Penrith's third win of the season and they went into the match sitting second to last on the NRL ladder.
"That was bitterly disappointing. It was terrible. We should have went on with that game (being up 28-6 at halftime) but we let them back into it - very disappointing....just silly errors and we gave them that game," said Warriors prop Jacob Lillyman.
The Panthers were booed by their own fans as they came off at halftime but by midway through the first half they had hit the lead and went on to snap a five-game losing streak and potentially igniting their season.
Isaah Yeo was the unlikely Penrith hero, scoring either side of halfltime before putting Waqa Blake through a hole, with the Panthers centre running over the top of Roger Tuivasa-Sheck to make it 28-24 after 56 minutes.
When Matt Moylan crossed in the 59th and Nathan Cleary potted the subsequent conversion, the Panthers had done the unthinkable and taken the lead.
Tyrone Peachey crossed four minutes from fulltime and Penrith were suddenly looking every bit the contenders many had tipped them to be this year.
The win will go down as one of the most memorable in the club's 50-year history.
It was the Panthers' second-biggest comeback, falling just short of the 23-point disadvantage they clawed back against the Wests Tigers in 2000.
It was an extraordinarily important two points in the context of the season as a loss would have almost spelled the end of their title hopes.
But instead the win lifts the Panthers to 3-7 and gives them confidence and belief heading in to next week's clash with Newcastle.
For the Warriors, it was their biggest collapse, eclipsing the 18-point lead they gave up against Manly in 2012.
It leaves Stephen Kearney's 4-6 side winless in Australia this year and will prompt big questions about their top eight chances.